PROGNOSTIC-SIGNIFICANCE OF SERUM LACTATE-DEHYDROGENASE IN PATIENTS WITH OSTEOSARCOMA OF THE EXTREMITIES

Six hundred and fifty-six patients with osteosarcoma of the extremitie s (107 metastatic and 549 with localized disease) were followed from 2 .5 to 20 years (average: 10 years) to evaluate whether their pretreatm ent serum lactate dehydrogenase (LDH) enzyme levels had a clinical val ue in predicting the course of the disease. The percentage of patients who had an elevated serum LDH at the time of diagnosis was significan tly higher in those patients with metastatic disease than those who ha d localized disease (64% versus 33%, p<0.0001). For those who presente d with localized disease and had an increased serum LDH level, far mor e ultimately developed a relapse of disease (60% versus 38%, p<0.0001) than those patients with a normal pre-treatment value. The prognostic significance of the serum LDH was more pronounced for the 247 patient s treated with adjuvant chemotherapy (relapse rate of 72% versus 48%: p<0.0002) than the 271 patients treated with neoadjuvant chemotherapy (relapse rate: 46% versus 28%, p<0.005). Following treatment, serum LD H levels almost uniformly returned to normal and no correlation betwee n postoperative levels and relapse of disease could be identified. We have demonstrated that in patients with osteosarcoma of the extremitie s, pretreatment serum LDH levels have a definite prognostic value whic h should be considered when comparing the results achieved with differ ent therapeutic protocols and in planning new randomized clinical tria ls.